KEY TO FAMILIES OF PISCES. 75 



*** Dorsal fms 2, the anterior of spines only, tlie posterior cliiclly of soft rays. 



M. Pectoral tin with 5 to 8 lowermost rays detached and fila- 

 mentous POLYNEMlDiE, G8. 



MM. Pectoral liu entire. 



N. Snout tubular, bearing the short jaws at the end ; body 



compressed Centriscid Ji, GO. 



NN. Snout not tubular. 



O. Teeth strong, unequal ; lateral lino present. 



Sphyr^nid^, 07. 

 00. Teeth small or wanting; lateral line obsolete. 

 P. Dorsal spines 4, stout; anal spines3..MuGiLiD,i2, G5. 

 PP. Dorsal spines 4 to 8, slender; anal spine single. 



Atherinidji:, G6. 

 *** Dorsal fin soft-rayed, followed by a series of detached Unlets. 



SCOMBERESOCID^, 57. 



(f *** Dorsal fin single, of soft rays only or with a single si:)ine. 

 a. Tail evidently heterocercal. 



b. Body naked; snout with a si^atulate blade; mouth wide, without barbel . 



PoLYODONTIDiE, "25. 



hh. Body with 5 series of body shields; mouth inferior, toothless, preceded by 4 



barbels Acipenserid^, 2lj. 



hbh. Body scaly. 



c. Scales cycloid ; a broad bony gular plate ; dorsal fin many-rayed. 



AMIlDiE, 23. 



cc. Scales ganoid ; no gular plate ; dorsal fin short Lepidosteid^e, 27. 



aa. Tail not evidently heterocercal. 



d. Body naked. 



e. Throat with a long barbel ; no caudal filament ; mouth large. 



SxOMIATIDiE, 4'). 



ee. Throat without barbel; caudal fin with a long filament ; mouth small. 



F1STULARIID.E, Gl. 

 ece. Throat without barbel ; no caudal filament; gill membranes joined to 



the isthmus CY'PRiNiDiE, 31. 



del. Body scaly. 



/. Pectoral fins inserted near the axis of the body ; lower jiharyngeal 



bones fully united ; lateral line along the 



sides of the belly.. .ScoMBERESOCiDiE, 57. 



ff. Pectoral fins inserted below the axis of the body ; lower pharyngeals 



separate. 



g. Vent in front of ventral fins; eyes concealed AMBLY'^OPSiDyE, 43. 



gg. Vent behind ventral fins; eyes normal. 

 /(. Head scaly, more or less. 

 i. Upper jaw not jirotractile, its lateral margin formed by the 

 maxillai'ies. 



j. Teeth cardiform ; jaws depressed, prolonged Esocid^, 51. 



jj. Teeth a' illiform ; jaws short Umisrid.e, 50. 



a. Upper jaw protractile, its margin formed by premaxillaries 

 alone C YPRINODONTIDiE, 49. 



hh. Head naked. 



Jc. Gill-opening separated by an isthmus; moftth toothless; 

 lower pharyngeals falciform. 



I. Dorsal fin with a serrated spine Cyprinidje, 31. 



II. Dorsal fin without serrated spine. 



m. Dorsal fin witli (usually) less than 10 (developed) rays; 

 pharyngeal teeth few (less than 8). 



CYPRINlDiE, 31. 



